全文获取类型
收费全文 | 411700篇 |
免费 | 19781篇 |
国内免费 | 9995篇 |
专业分类
化学 | 222384篇 |
晶体学 | 5468篇 |
力学 | 21009篇 |
综合类 | 519篇 |
数学 | 48356篇 |
物理学 | 143740篇 |
出版年
2022年 | 3762篇 |
2021年 | 6085篇 |
2020年 | 7151篇 |
2019年 | 7171篇 |
2018年 | 8234篇 |
2017年 | 8142篇 |
2016年 | 11719篇 |
2015年 | 8208篇 |
2014年 | 12026篇 |
2013年 | 22328篇 |
2012年 | 20170篇 |
2011年 | 22960篇 |
2010年 | 16392篇 |
2009年 | 16144篇 |
2008年 | 18826篇 |
2007年 | 18060篇 |
2006年 | 16715篇 |
2005年 | 14156篇 |
2004年 | 12639篇 |
2003年 | 10876篇 |
2002年 | 10680篇 |
2001年 | 12034篇 |
2000年 | 9138篇 |
1999年 | 7718篇 |
1998年 | 6486篇 |
1997年 | 6318篇 |
1996年 | 5974篇 |
1995年 | 5151篇 |
1994年 | 4930篇 |
1993年 | 4670篇 |
1992年 | 4920篇 |
1991年 | 4978篇 |
1990年 | 4624篇 |
1989年 | 4389篇 |
1988年 | 4050篇 |
1987年 | 4146篇 |
1986年 | 3932篇 |
1985年 | 4816篇 |
1984年 | 4768篇 |
1983年 | 3943篇 |
1982年 | 4004篇 |
1981年 | 3693篇 |
1980年 | 3633篇 |
1979年 | 3888篇 |
1978年 | 3863篇 |
1977年 | 3881篇 |
1976年 | 3861篇 |
1975年 | 3639篇 |
1974年 | 3591篇 |
1973年 | 3623篇 |
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
101.
Dr. Yulia Y. Enakieva Dr. Anna A. Sinelshchikova Prof. Mikhail S. Grigoriev Prof. Vladimir V. Chernyshev Dr. Konstantin A. Kovalenko Prof. Irina A. Stenina Prof. Andrey B. Yaroslavtsev Prof. Yulia G. Gorbunova Prof. Aslan Y. Tsivadze 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(45):10552-10556
The design of new solid-state proton-conducting materials is a great challenge for chemistry and materials science. Herein, a new anionic porphyrinylphosphonate-based MOF ( IPCE-1Ni ), which involves dimethylammonium (DMA) cations for charge compensation, is reported. As a result of its unique structure, IPCE-1Ni exhibits one of the highest value of the proton conductivity among reported proton-conducting MOF materials based on porphyrins (1.55×10−3 S cm−1 at 75 °C and 80 % relative humidity). 相似文献
102.
A Savitzky–Golay filtering for smoothing and peak search written in Python is presented in this paper alongside its applications in the list-mode digital data acquisition dual gamma–gamma coincidence bismuth germanate (BGO) detector. The study has demonstrated that the software provides a reliable and effective way to quantify trace amounts of 22Na and 7Be in aerosol samples collected at Resolute Bay, Canada with a critical limit of 3 mBq and 5 Bq respectively for a 20 h counting interval, which are believed to be the inherent limitations of the dual-BGO system.
相似文献103.
104.
Yanxia Xu Yanbing Lv Ruili Wu Huaibin Shen Huawei Yang Han Zhang Jinjie Li Lin Song Li 《Particle & Particle Systems Characterization》2020,37(3):1900441
Indium phosphide (InP) quantum dots (QDs) are ideal substitutes for widely used cadmium-based QDs and have great application prospects in biological fields due to their environmentally benign properties and human safety. However, the synthesis of InP core/shell QDs with biocompatibility, high quantum yield (QY), uniform particle size, and high stability is still a challenging subject. Herein, high quality (QY up to 72%) thick shell InP/GaP/ZnS core/shell QDs (12.8 ± 1.4 nm) are synthesized using multiple injections of shell precursor and extension of shell growth time, with GaP serving as the intermediate layer and 1-octanethiol acting as the new S source. The thick shell InP/GaP/ZnS core/shell QDs still keep high QY and photostability after transfer into water. InP/GaP/ZnS core/shell QDs as fluorescence labels to establish QD-based fluorescence-linked immunosorbent assay (QD-FLISA) for quantitative detection of C-reactive protein (CRP), and a calibration curve is established between fluorescence intensity and CRP concentrations (range: 1–800 ng mL−1, correlation coefficient: R2 = 0.9992). The limit of detection is 2.9 ng mL−1, which increases twofold compared to previously reported cadmium-free QD-based immunoassays. Thus, InP/GaP/ZnS core/shell QDs as a great promise fluorescence labeling material, provide a new route for cadmium-free sensitive and specific immunoassays in biomedical fields. 相似文献
105.
为了寻求新型蚜虫控制剂,以蚜虫报警信息素(E)-β-farnesene(EBF)为先导,引入不同类型的杂环取代EBF结构中不稳定的共轭双键,设计合成了一系列不同杂环取代的EBF类似物.所有化合物结构均通过1H NMR、13C NMR、IR及HRMS确证.对化合物进行了生物活性测试及初步构效关系分析.结果表明,所有化合物均对桃蚜和大豆蚜表现出一定的生物活性,部分化合物的杀虫活性优于先导EBF,酯基的引入则对驱避活性有利. 相似文献
106.
Knyazev A. A. Karyakin M. E. Krupin A. S. Galyametdinov Yu. G. 《Russian Journal of General Chemistry》2015,85(12):2806-2812
Russian Journal of General Chemistry - Hybrid liquid crystal systems with different ratios of the components have been prepared on the basis of 5,5′-di(heptadecyl)-2,2′-bipyridine... 相似文献
107.
108.
109.
Jing Zhihong Ling Baoping Yu Yang Qi Wei Zhang Shufang 《Journal of Sol-Gel Science and Technology》2015,73(1):112-117
Journal of Sol-Gel Science and Technology - A novel gas sensing material, La–Y co-doped TiO2 nanoparticles, was synthesized by sol–gel method and applied to detect organic pollutants... 相似文献
110.